Fine structure of ortho-and para-D2 d(3p) 3Πu via microwave optical magnetic resonance induced by electrons

Abstract

The MOMRIE (microwave optical magnetic resonance induced by electrons) spectrum has been measured for ortho‐D₂ d(3p) ³Π_u in vibrational levels v = 0−4 and for para‐D₂ in vibrational levels v = 0−5. The theory used to analyze these spectra is identical to that used previously to analyze the MOMRIE spectrum of para‐H₂. Least squares fits to the data provide values for the so‐called spin‐orbit and spin‐spin coupling constants, the orbital g factor, and the magnetic and electric susceptibilities. Differences between the constants for ortho‐ and para‐D₂ demonstrate significant breakdown of the Born‐Oppenheimer approximation. Zero field fine structure separations have been calculated from the molecular parameters. Hyperfine structure is smaller than the natural linewidth and so is unresolved. It does broaden the lines, however, by an amount which is consistent with expectations.